[PATCH] D132900: [DWARF] Fix infinite recursion in Type Printer.

[Alexander Yermolovich via Phabricator via llvm-commits]

ayermolo created this revision.
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There is an implicit circular dependency in a debug information coming from GCC.
This results in a coredump.

0x0066ec56: DW_TAG_formal_parameter [3]   (0x0066ec48)

  DW_AT_type [DW_FORM_ref4]	(cu + 0x168fa => {0x0066ec5b}

"
appendQualifiedName: 66ec5b
appendScopes:	66ec48
appendUnqualifiedName:	66ec48
appendUnqualifiedNameBefore:	66ec48
appendQualifiedNameBefore:	66597f
appendScopes:	665972
appendScopes:	65838b
appendUnqualifiedName:	65838b
appendUnqualifiedNameBefore:	65838b
sappendUnqualifiedNameAfter:	65838b
appendUnqualifiedName:	665972
appendUnqualifiedNameBefore:	665972
appendUnqualifiedNameAfter:	665972
appendUnqualifiedNameBefore:	66597f
appendUnqualifiedNameAfter:	66ec48
appendUnqualifiedName:	66ec48
appendQualifiedName: 66ec5b
appendScopes:	66ec48

TBH not sure if this is the correct fix or not.
Thoughts appreciated.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D132900

Files:
  llvm/include/llvm/DebugInfo/DWARF/DWARFTypePrinter.h
  llvm/lib/DebugInfo/DWARF/DWARFTypePrinter.cpp


Index: llvm/lib/DebugInfo/DWARF/DWARFTypePrinter.cpp
===================================================================
--- llvm/lib/DebugInfo/DWARF/DWARFTypePrinter.cpp
+++ llvm/lib/DebugInfo/DWARF/DWARFTypePrinter.cpp
@@ -283,8 +283,12 @@
 }
 
 void DWARFTypePrinter::appendQualifiedName(DWARFDie D) {
-  if (D)
+  if (D) {
+    if (CircularDep.contains(D.getOffset()))
+      return;
+    CircularDep.insert(D.getOffset());
     appendScopes(D.getParent());
+  }
   appendUnqualifiedName(D);
 }
 DWARFDie DWARFTypePrinter::appendQualifiedNameBefore(DWARFDie D) {
Index: llvm/include/llvm/DebugInfo/DWARF/DWARFTypePrinter.h
===================================================================
--- llvm/include/llvm/DebugInfo/DWARF/DWARFTypePrinter.h
+++ llvm/include/llvm/DebugInfo/DWARF/DWARFTypePrinter.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_DEBUGINFO_DWARF_DWARFTYPEPRINTER_H
 #define LLVM_DEBUGINFO_DWARF_DWARFTYPEPRINTER_H
 
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
@@ -25,6 +26,7 @@
   raw_ostream &OS;
   bool Word = true;
   bool EndedWithTemplate = false;
+  SmallSet<uint64_t, 5> CircularDep;
 
   DWARFTypePrinter(raw_ostream &OS) : OS(OS) {}
 


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